Role of Ryanodine Receptor Subtypes in Initiation and Formation of Calcium Sparks in Arterial Smooth Muscle: Comparison with Striated Muscle
Figure 3
In vivo suppression of RyR2 expression by antisense oligonucleotides (AS ODNs) in rat cerebral artery smooth muscle cells leads to increase of SR content without effects on spontaneous calcium sparks. (a) Left side: Images of rat cerebral arteries isolated 7 days after continuous i.c.v. injection of the fluorescence-labled AS ODNs (left) and nonlabeled AS ODNs (right) via Alzet osmotic pumps. Right side: RyR2 mRNA expression normalized to 18S ribosomal mRNA expression in arteries isolated from rats treated by AS ODNs (red) and scrambled (SC) ODNs (black) ( rats in each group). (b) Left side: Averaged time course of changes in response to external 10 mM caffeine in fluorescence intensity in Fluo-4 loaded cerebral artery smooth muscle cells (SMCs) isolated from rats treated with AS ODNs (red) and SC ODNs (black). The corresponding mean peak amplitudes are presented in the middle plot. Right side: The frequency of calcium sparks was not different between AS and SC ODNs treated cells. Calcium sparks were recorded in line-scan mode. The number of cells tested is indicated above each bar. Data are mean S.E.M. AU: arbitrary unit.
